Acid dyeing isotherms of cotton fabrics pretreated with mixtures of reactive cationic agents

Abstract

Reactive cationic agents, phenylmonochlorotriazinyl and epoxypropyl, are used for cotton pretreatment using a pad–dry–curing technique. The dyeability of cationised cotton fabrics using CI Acid Red 1, determined spectrophotometrically for the residual dyebath, has been dependent on the cationic agent concentration and the appropriate mixture used. Comparative sorption isotherms, rate of dyeing at different temperatures, standard affinity, entropy and heat of dyeing for three different pretreated fabrics have been calculated and discussed. The equilibrium data obtained were fitted by the Langmuir isotherm model, allowing the corresponding sorption parameters to be determined.